In disc storage systems, as technical development continuously moves to higher storage capacities, the mechanical construction of the head positioner device must likewise be improved. A typical high capacity disc storage system includes a plurality of discs which are stacked on a centrally located spindle. Compact construction of the device requires minimal disc separation between the stacked discs. Fast access to the information stored on the discs requires a low inertia positioner with a short settling time and good damping characteristics after positioning. With a fast servo for positioning, the positioner should be constructed to have high resonant frequencies with good signal following properties and a short response time. Two different types of positioning devices are known: namely, linear positioners and rotational positioners.
A linear positioner is moved radially with respect to the disc by means of an actuator pulse system during track selection. A rotational positioner is rotatably mounted on a positioning axis arranged parallel to the axis of the disc stack. The rotational positioner has on one side of the positioning axis positioning arms for carrying the read/write heads and on the other side of the positioning axis a pair of carrier arms. The carrier arms carry either a coil which influences a fixed magnet or a magnet, in which case the coil is fixed.
In more recent constructions of a positioner device, a monolithic body with integral positioning arms and integral carrier arms has been used, which is conventionally known as an "E-block". Such an E-block has the advantage that smaller inner stresses arise and the number of connections is minimized, so that the time required to position the arm is short.
With increasing miniaturization of the disc storage system and the positioning device, the manufacture of a monolithic E-block is, however, exceptionally difficult, laborious and accordingly expensive.
It accordingly is the problem of the invention to create a positioner in which the advantages of the monolithic E-block can essentially be maintained but in which the necessary high precision of the complex structure can be achieved in a simpler and accordingly more cost favorable fashion.